1. Field of the Invention
This invention relates to a manual reverse control for a manually operable automatically controlled vehicle. In one of its aspects, the invention relates to a means for manually driving an automatically controlled vehicle in a reverse direction when other manual controls at the front of the vehicle are inaccessible due to the presence of an obstacle abutting the front of the vehicle.
2. State of the Prior Art
Various service vehicles have been provided with automatic controls so that they are driven on a predetermined guide path in a programmed manner. In such vehicles, the guide paths, such as reflected guidelines or electrically detectable guide wires, are positioned on or in the floor. For example, in U.S. Pat. No. 3,628,624 to Wesener, issued Dec. 21, 1971, a vehicle which follows a predetermined guide path has a control panel at the front end of the vehicle for presetting a reader to respond to code markings along the guide path. A reversing switch is provided on a control panel to reverse the functions of the automatic guide system so that the vehicle follows the guide path in a reverse direction.
An automatically controlled vehicle with a manual override is disclosed in the U.S. Pat. to Kohls, No. 3,557,893, issued Jan. 26, 1971. In the Kohls vehicle, a tiller, pivotably mounted on a vertical steering shaft, is biased to a normally inoperative vertical position. Movement of the tiller downwardly to an operative position deactivates the automatic steering system, disconnects the steering servomotor, and activates a control unit operated by a handle on the tiller for propulsion regulation and steering of the vehicle.
The tiller control system provides a convenient method of manually steering the vehicle while manually controlling the propulsion of the vehicle. The disadvantage to this system is that the tiller handle must be pulled down forwardly of the vehicle in order to activate the manual control system. In the event that an obstacle such as a wall is struck by the front of the vehicle, it may not be possible to pull the tiller down so that the manual control can be used to operate the vehicle. In such cases, the vehicle must be pushed backward manually or lifted backwardly a distance sufficient to operate the tiller handle. If the brakes of the vehicle have been applied, lifting may be the only way to position the vehicle back from the obstacle in order to achieve the manual controls.
In certain types of uses for automatically controlled vehicles, it is desired to place the tiller or other manual controls behind a front door. Removal or pivoting of the door to reach the manual controls is equally difficult if the front of the vehicle is abutting an obstacle.